Heterogeneous Power Amplifier Linearization With Adaptive Predistortion
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Solution Overview
Problem
Heterogeneous multiple amplifier systems face challenges in linearization due to non-linear interactions between amplifier devices, requiring optimization beyond typical efficiency considerations to coordinate bandwidth, amplitude, and total distortion, especially in radio frequency (RF) communication systems.
Innovation Solution
A method involving a signal processing component that characterizes amplifier paths through an iterative adaptive linearization process, using predistortion functions to optimize system output by subtracting the expected contributions of non-selected amplifier paths and refining predistortion functions to achieve a linear response, involving a monitoring system and signal combiner to normalize and combine amplified outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If heterogeneous amplifier paths are used to increase output power and efficiency, then system efficiency and power output are improved, but non-linear interactions between amplifier devices cause distortion and deviation from ideal linear amplification
Solution Approach 1:
The system divides the amplification function into multiple separate amplifier paths (main amplifier path and auxiliary amplifier path), each with its own predistortion component. This segmentation allows independent optimization of each path while managing their combined non-linear interactions through iterative adaptive linearization.
Solution Approach 2:
Predistortion functions are applied to the input signal before amplification to pre-compensate for expected non-linearities. The main predistortion component and auxiliary predistortion component apply corrections in advance, so that when the heterogeneous amplifiers introduce non-linear effects, the overall system response remains linear.
Solution Approach 3:
The system employs iterative adaptive linearization where the output of the heterogeneous amplifier system is monitored and fed back to adjust the predistortion functions. By measuring the actual output and comparing it to the desired linear response, the predistortion parameters are continuously refined to compensate for non-linear interactions between the amplifier paths.
2Power
If multiple heterogeneous amplifier devices are coordinated to provide higher output, then power output is improved, but complexity of coordinating bandwidth, amplitude, and total distortion increases
Solution Approach 1:
The main amplifier path and auxiliary amplifier path are combined through a signal combiner to provide increased output power. The merging of these paths is managed through coordinated predistortion and iterative adaptive linearization, which simplifies the coordination complexity by providing a unified control framework for managing bandwidth, amplitude, and distortion across both paths.
Solution Approach 2:
The iterative adaptive linearization process serves multiple functions simultaneously: it linearizes the amplitude response, manages bandwidth considerations, and controls total distortion. This multi-functional approach reduces coordination complexity by consolidating what would otherwise require separate control mechanisms for each parameter.
3Manufacturing precision
If predistortion functions are applied to linearize amplifier output, then linearity is improved, but complexity of determining and refining predistortion functions increases
Solution Approach 1:
The predistortion function is segmented into separate components: a main predistortion component for the main amplifier path and an auxiliary predistortion component for the auxiliary amplifier path. This segmentation allows each predistortion function to be optimized independently for its specific amplifier path, reducing the overall complexity compared to designing a single complex predistortion function for the entire system.
Solution Approach 2:
The predistortion functions are made dynamic through iterative adaptive linearization. Rather than using fixed predistortion parameters, the system continuously adapts the predistortion functions based on measured system performance. This dynamic adjustment simplifies the design process by allowing the system to automatically optimize linearity without requiring manual tuning of complex predistortion parameters.
Data Source
AI summary
Systems and methods are provided for adaptive linearization of an amplifier system having a plurality of heterogeneous amplifier paths. An amplifier system includes a plurality of amplifier paths, each configured to provide an amplified output signal from an input signal, and a signal combiner configured to combine the amplified output signals from the plurality of amplifier paths to provide a system output, such that the system output is a non-linear function of the amplified output signals. A monitoring system is configured to sample the system output and normalize the sampled output to a signal level associated with the input signal. A signal processing component is configured to characterize the amplifier paths via an iterative adaptive linearization process, such that the system output is linear with respect to the input signal.